This week I'll write about a fish I've apparently never written about before. Of course there are a few thousand that could meet that requirement, but there is a special reason for writing about this one. Along with other migrants from south of the border, the reef cornetfish (Fistularia commersonii) has entered the waters of southern California. Along with the changes in our local waters I've outlined in the previous three columns, the appearance of warmer water species like this have also altered species composition in what's left of our local kelp forests.
I've often encountered various species of cornetfish while diving tropical waters. They are very unusual fish. Their bodies are very long and slender. The reef cornetfish may reach a maximum length of over five feet. It has an unusual tubular snout, long and pointed, with small teeth. The tail is thin and whiplike. Body color may include bars or stripes, with the barred phase generally used for camouflage when resting or at night.
Geographically this species has a wide range throughout tropical waters. Along the west coast of North America, it is generally not seen above Magdalena Bay in Baja California. Its appearance in our waters probably represents an historic extension of its range. Sightings in southern California have been limited to Laguna Beach and San Clemente Island and have been limited in number. That does not bode well for its continued existence here since it takes two to tango... or reproduce the species if you will. Without that and continued survival here once the waters cool down, it will simply be a short-term member of our ecosystems.
Cornetfish are sometimes called flutemouths. They are occasionally confused with trumpetfish (Aulostomus maculatus), which are also called flutemouths. However, despite similarities in body shape, the two groups are in different fish families. The mouths are shaped differently and the trumpetfish has a short, somewhat broad tail compared to the cornetfish's long whip-like one. Both are commonly found over reefs and sandflats in tropical waters. I find it amusing that they are named after brass instruments. I am tone deaf and almost flunked 8th grade music, and was told by my junior high school band leader NOT to blow through the mouthpiece of my trombone!. However, as a marine biologist, I have no problem telling the difference between the two. That could be because neither produces a single musical note as far as I know!
One would think a fish of this size would have trouble obtaining a meal since it could be seen easily. However, given their slender shape and ability to change body coloration, they are able to stalk prey. You can often see them hanging motionless in the water column waiting for a juicy meal to appear. Their diet includes blenny-like fish, halfbeaks, herring and snake eels. I wonder what our local individuals find tasty here? I think it is pretty obvious from looking at their bodies that despite their length, they would not make a substantial meal for humans. Not much meat on those bones! They are not really targeted commercially, although I did find references to their being ground up for fish meal.
Thanks to The Blob and el Niño, we have had quite a number of visitors from warm water regions. Quite the reverse from the "snowbirds" (formerly including my parents) that would migrate from cold climates like Chicago to warmer winter habitats like Florida. I've been very pleased to follow the exploits of our little whitetail gregory (Stegastes leucorus) and the cardinalfish in the dive park.
When fish like these enter new regions, I often wonder just what they find to eat. Obviously this is a "must do" if they are to survive in the new location. If they find palatable prey (or seaweed for the vegetarian and vegan species), they can achieve "ecological establishment," adapting not only to the prevailing environmental conditions but also finding sufficient munchies to grow... and hopefully reproduce. Kind of like when I travel to exotic dive destinations and have to adapt to local foods instead of hitting McDonalds. Oh, wait... we don't have those here on our island!
© 2015 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!
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Cornetfish (top) and trumpetfish (bottom) from tropical waters.
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Dr. Bill Bushing.
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